Electroplating apparatus

ABSTRACT

An electroplating apparatus includes an electroplating tank, a first anode plate, a first cathode plate, a second cathode plate, a number of first and second elastic elements, a number of pairs of clamping assemblies, a first drive member, and a second drive member. The electroplating tank holds an electrolyte solution. The first elastic elements are interconnected between the first anode plate and the first cathode plate. The second elastic elements are interconnected between the first anode plate and the second cathode plate. Each pair of clamping assemblies are used to clamp opposite ends of a plated-shaped workpiece. The first drive member and the second drive member are used to cooperatively move the clamping assemblies.

BACKGROUND

1. Technical Field

The disclosure relates to electroplating and, particularly, to an electroplating apparatus for applying a uniform layer on a surface of a workpiece.

2. Description of Related Art

Currently, electroplating is generally used for depositing a layer of material, such as metal on a surface of a workpiece. The workpiece may be, for example, a printed circuit board (PCB). Many electroplating apparatuses include an electroplating tank holding electrolyte solution, an anode plate, a cathode plate, and a conductive clip. In operation, the workpiece is clamped to the cathode plate by the clip, and an electric current is applied to the workpiece through the clip. However, one drawback is that the workpiece is easily clamped too tightly or too loosely. When the workpiece is clamped too tightly, the workpiece may be distorted. When the workpiece is clamped too loosely, the workpiece is too easily detached from the clip. Another drawback is that current density applied to the surface of the workpiece at a position close to the clip is generally greater than at any position farther from the clip. The non-uniform current density tends to result in non-uniform thickness of the metallic layer formed on the surface of the workpiece.

Therefore, what is needed is an electroplating apparatus which can overcome the limitations described.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

FIG. 1 is a sectional view of an electroplating apparatus according to an embodiment.

FIG. 2 is a top plan view of the electroplating apparatus of FIG. 1.

FIG. 3 is a cutaway view of the electroplating apparatus of FIG. 1.

FIG. 4 is an isometric view of two neighboring assemblies of FIG. 1, together with a workpiece.

FIG. 5 is an isometric view of a single clamping assembly, showing the clamping assembly being in an unfolded state.

DETAILED DESCRIPTION

Embodiment of the disclosure will now be described in detail below with reference to drawings.

Referring to FIG. 1 to FIG. 3, an electroplating apparatus 100 according to an embodiment is shown. The electroplating apparatus 100 includes an electroplating tank 11, a first support member 12, a second support member 13, a first drive member 14, a second drive member 15, a number of pairs of clamping assemblies 16, a first anode plate 17, a second anode plate 18, a first cathode plate 19, a second cathode plate 20, a number of first elastic elements 21A, a number of second elastic elements 21B, and an ion density adjustment member 22.

The tank 11 can be generally frusto-conical shaped, and has a vertical centerline M. The tank 11 includes a bottom board 110 and a holder 111. The bottom board 110 is substantially horizontally oriented. The holder 111 extends up from a peripheral portion of the bottom board 110. The electroplating tank 11 holds an electrolyte solution 112. In this embodiment, the electrolyte solution 112 can be a liquid mixture containing for example, copper sulfate, sulfuric acid, hydrochloric acid. The first anode plate 17, the second anode plate 18, the first cathode plate 19, the second cathode plate 20, and the first and the second elastic elements 21A and 21B are immersed in the solution 112.

The first support member 12 includes a loading board 120 and a retracting board 121. The loading board 120 includes a first end 120A, an opposite second end 120B, and a recessed portion 120C. The first end 120A and the opposite second end 120B are horizontally oriented, and protrude from the solution 112. The recessed portion 120C is located between and connected to the first end 120A and the second end 120B. In addition, the recessed portion 120C is immersed in the solution 112. In this embodiment, the recessed portion 120C is generally trapezoid-shaped, and tapers toward the bottom board 110 (or tapers away from the first end 120A and the second end 120B). The recessed portion 120C has a base 124, a first sidewall 125, and a second sidewall 126. The first sidewall 125 and the second sidewall 126 are located at opposite sides of the base 124. In this embodiment, the first sidewall 125 is located between and connected to the first end 120A and the base 124. The second sidewall 126 is located between and connected to the second end 120B and the base 124. The base 124 is substantially parallel to the bottom board 110. Each of the first sidewall 125 and the second sidewall 126 is slanted relative to the base 124.

The retracting board 121 is similar to the loading board 120 in structure. In this embodiment, the retracting board 121 is located below the loading board 120. Opposite ends of the retracting board 121 are connected to the respective first and second ends 120A and 120B of the loading board 120. With this configuration, the first support member 12 is generally circular.

As shown in FIG. 3, the second support member 13 is similar to the first support member 12 in structure. In this embodiment, the second support member 13 and the first support member 12 are symmetrical relative to each other across the centerline M of the tank 11. In addition, the first support member 12 and the second support member 13 are made of polyvinylchloride (PVC).

The first drive member 14 is arranged on the first support member 12. The second drive member 15 is arranged on the second support member 13. In this embodiment, each of the first drive member 14 and the second drive member 15 is a conveyor belt. In operation, a portion of the conveyor belt on the retracting board 121 is retracted to the loading board 120 alternately. Each of the first drive member 14 and the second drive member 15 can be made of rubber-like material, and can be driven by sprockets (not shown). In alternative embodiments, each of the first drive member 14 and the second drive member 15 may be a timing belt with transverse grooves (not shown).

In operation, a workpiece 200 (see FIG. 4) can be loaded on the first drive member 14 and the second drive member 15 at the first ends 120A of both the first and the second support members 12 and 13. The first drive member 14 and the second drive member 15 cooperate to transport the workpiece 200 from the first ends 120A to the second ends 120B through the recessed portions 120C. When the workpiece 200 is transported to the second ends 120B, the workpiece 200 can be unloaded.

When the workpiece 200 is located in the recessed portion 120C and immersed in the solution 112, electroplating can be applied to the workpiece 200, to deposit a layer of material, such as metal on a surface of the workpiece 200. The workpiece 200 can, for example, be a printed circuit board (PCB). As shown in FIG. 4, the workpiece 200 in this embodiment is rectangular plate-shaped, and includes a first surface 201 and an opposite second surface 202.

Referring to FIG. 4 and FIG. 5, each of the clamping assemblies 16 is arranged between the first drive member 14 and the second drive member 15. In this embodiment, the clamping assemblies 16 are arranged as cross pieces between the first and the second support members 12 and 13. The clamping assemblies 16 are spaced from one another. In addition, as shown in FIG. 4, each pair of clamping assemblies include two neighboring clamping assemblies 16. The two neighboring clamping assemblies 16 cooperate to engagingly clamp a workpiece 200 at opposite edge portions of the workpiece 200.

FIG. 5 shows a single clamping assembly in an unfolded state. The clamping assembly 16 includes a first clamping board 162, a second clamping board 164, and a shaft 163. The second clamping board 164 is pivotably coupled to the first clamping board 162 via the shaft 163. The two shafts 163 of the two clamping assemblies 16 are substantially parallel to each other. In this embodiment, each of the first clamping board 162 and the second clamping board 164 are substantially cuboid-shaped. The first clamping board 162 is longer than the second clamping board 164 in a direction parallel to the shaft 163. With this configuration, the second clamping board 164 can be rotated relative to the first clamping board 162, and the workpiece 200 can be clamped between the first clamping board 162 and the second clamping board 164. When the workpiece 200 is clamped, opposite ends 1620 of the first clamping board 162 protrude from the second clamping board 164 (see FIG. 4).

Each of the first clamping board 162 and the second clamping board 164 includes a first conductive layer 16A, a second conductive layer 16B, and a magnetic layer 16C. The first and the second layers 16A and 16B are substantially parallel to each other. The magnetic layer 16C is sandwiched between the first and the second layers 16A and 16B. The magnetic layer 16C can be made of magnet. In operation, an electromagnetic force is generated between the first magnetic layer 16A of the first clamping board 162 and the first magnetic layer 16A of the second clamping board 164. The electromagnetic force is applied to either of the first clamping board 162 and the second clamping board 164 to move the first and the second clamping boards 162 and 164 toward each other. When the workpiece 200 is arranged between the first clamping board 162 and the second clamping board 162, the workpiece 200 is tightly clamped. In this embodiment, as shown in FIG. 4, when the workpiece 200 is clamped, the first conductive layers 16A of the first and the second clamping boards 162 and 164 intimately contact the respective first and second surfaces 201 and 202 of the substrate 200.

The first anode plate 17 and the second anode plate 18 are arranged at opposite sides of the recessed portions 120C, and are substantially parallel to each other. The second anode plate 18 is close the bottom board 110, and the first anode plate 17 is farther from the bottom board 110. The first anode plate 17 can be fixed to, for example, the holder 111, in a manner that the first anode plate 17 is horizontally oriented. In this embodiment, the second anode plate 18 is arranged between the loading board 120 and the retracting board 121. Four first holding bars 180 are provided and used to connect the second anode plate 18 to the loading board 120. The first anode plate 17 and the second anode plate 18 both are substantially cuboid-shaped. The four first holding bars 180 are uniformly dispersed on the second anode plate 18, and connected to four respective corners of the second anode plate 18. In this embodiment, each of the first and the second anode plates 17 and 18 can be made of titanium. The first holding bars 180 can be made of PVC.

The first and the second cathode plates 19 and 20 are spaced from the first anode plate 17 by the first and the second elastic elements 21A and 21B (see FIG. 3). In this embodiment, four second holding bars 170, a first support bars 210A, and a second support bar 210B are provided to connect the first and the second elastic elements 21A and 21B to the first anode plate 17.

Each of the first and the second support bars 210A and 210B is strip-shaped. The first support bar 210A is substantially parallel to the second support bar 210B. In this embodiment, two second holding bars 170 are interconnected between the first anode plate 17 and the first support bar 210A. The other two second holding bars 170 are interconnected between the first anode plate 17 and the second support bar 210B.

In this embodiment, the electroplating apparatus 100 includes five first elastic elements 21A and five second elastic elements 21B. The first elastic elements 21A are interconnected between the first cathode plate 19 and the first support bar 210A. The second elastic elements 21B are interconnected between the second cathode plate 20 and the second support bar 210B.

In this embodiment, each of the holding bars 170, the first and the second support bars 210A and 210B can be made of PVC. Each of the first and the second elastic elements 21A and 21B can be a metal spring.

Each of the first and the second cathode plates 19 and 20 is strip-shaped, and can be made of graphite. Each of the first and the second cathode plates 19 and 20 is substantially parallel to the first support bar 210A or the second support bar 210B. In this embodiment, the first and second cathode plates 19 and 20 are located near to the bottom bases 124 of the first and the second support members 12 and 13. When the workpiece 200 is transported to a location on the bases 124 of the first and the second support members 12 and 13, the first and the second elastic elements 21A and 21B elastically press the first anode plate 19 and the second anode plate 20 toward the first conductive layers 16A of the clamping assemblies 16. The first anode plate 19 and the second anode plate 20 thus electrically contact the opposite ends 1620 of the first conductive layers 16A.

The electroplating apparatus 100 may include a power supply (not shown) and a commutator. The commutator generally includes an anode terminal and a cathode terminal. In this embodiment, the first and the second anode plates 17 and 18 are connected in parallel, and further connected to the anode terminal of the commutator. The first and the second cathode plates 19 and 20 are connected in parallel, and further connected to the cathode terminal of the commutator.

The ion density adjustment member 22 includes an ion supplying vessel 220, a tube 221, an ion density detector 222, a controller 223, and a pump 224. The ion supplying vessel 220 contains solution. In this embodiment, the solution of the vessel 220 contains sulfuric acid. The sulfuric acid is used to dissolve copper oxide powder to generate copper ion in the solution. The tube 221 can be a pipe or a hose. An end of the tube 221 is immersed in the solution 112 of the tank 11, an opposite and of the tube 221 is immersed in the solution of the vessel 220. The pump 224 is connected to the tube 221. In operation, the detector 222 is used to detect density of the positive ion in the solution 112, and generate a detecting signal to the controller 223.

In this embodiment, the solution 112 contains copper sulfate. In operation, the power supply supplies a direct current to the solution 112 to generate copper ions. The copper ions in the solution 112 generate a chemical reaction to produce Cu. The produced Cu is gradually deposited on the first and the second surfaces 201, 202 of the workpiece 200. Thus, a copper layer is formed on the first and the second surfaces 201 and 202. In one example that illustrates operation of the ion density adjustment member 22, when the ion density of the solution 112 decreases to below a predetermined value, the pump 224 is controlled by the controller 223 to switch on. The solution in the vessel 220 is pumped into the solution 112 by the pump 224. Thus, copper ions are supplied into the solution 112 until density of the copper ions in the solution 112 achieves the predetermined value.

One advantage of the electroplating apparatus 100 is that the electroplating apparatus 100 is equipped with a first drive member 14, a second drive member 15, a number of clamping assemblies 16, and a number of first and second elastic elements 21A and 21B. A number of pairs of clamping assemblies 16 are used to clamp the substrate 200. Each clamping assembly 16 has two first conductive layers 16A to intimately contact the respective first and second surfaces 201 and 202 of the substrate 200. The first and the second elastic elements 21A and 21B are used to elastically press the first anode plate 19 and the second anode plate 20 toward the first conductive layers 16A of the clamping assemblies 16. The first anode plate 19 and the second anode plate 20 electrically contact the first conductive layers 16A. With this configuration, in one aspect, when the clamping assembly 16 clamps the substrate 200, the first drive member 14 and the second drive member 15 cooperatively support each clamping assembly 16. The substrate 200 thus can be clamped firmly and transported steadily. In another aspect, current density can be uniformly applied to the workpiece 200 via the two first conductive layers 16A, thus current density applied to the workpiece 200 is uniform across the first and the second surfaces 201 and 202. Uniform copper layers can be deposited across each of the first and the second surfaces 201 and 202.

It is understood that the embodiments disclosed are intended to illustrate rather than limit the disclosure. Variations may be made to the embodiment without departing from the spirit of the disclosure. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the disclosure. 

1. An electroplating apparatus, comprising: an electroplating tank for containing an electrolyte solution; a first anode plate arranged in the electrolyte solution; a first cathode plate and a second cathode plate opposite to the first cathode plate; a plurality of first elastic elements interconnected between the first anode plate and the first cathode plate; a plurality of second elastic elements interconnected between the first anode plate and the second cathode plate; a plurality of pairs of clamping assemblies, each pair of the clamping assemblies configured for clamping opposite ends of a plated-shaped workpiece; and a first drive member and a second drive member arranged at opposite ends of each clamping assembly, the first drive member and the second drive member configured for cooperatively moving the clamped workpieces in the electrolyte solution, the first and the second elastic elements configured for elastically pressing the first cathode plate and the second cathode plate toward at least one of the clamping assemblies such that the first cathode plate and the second cathode plate electrically contact opposite ends of the at least one of the clamping assemblies, and the workpiece clamped by the at least one of the clamping assemblies is oriented toward the first anode plate.
 2. The electroplating apparatus of claim 1, wherein each of the clamping assemblies comprises: a first clamping board; a shaft; and a second clamping board, the second clamping board pivotedly connected to the first clamping board via the shaft, the first clamping board and the second clamping board configured for sandwiching the workpiece therebetween.
 3. The electroplating apparatus of claim 2, wherein each of the first clamping board and the second clamping board comprises: a first conductive layer; a second conductive layer; and a magnetic layer sandwiched between the first conductive layer and the second conductive layer, wherein the magnetic layers of the first clamping board and the second clamping board configured for generating an electromagnetic force to pull the first clamping board and the second clamping board toward each other, such that the workpiece is clamped by and between the first conductive layer of the first clamping board and the first conductive layer of the second clamping board.
 4. The electroplating apparatus of claim 3, wherein each of the first clamping board and the second clamping board is cuboid-shaped, and the first clamping board is longer than the second clamping board along a direction parallel to the shaft, the first cathode plate and the second cathode plate respectively contact opposite ends of the first conductive layer of the first clamping board.
 5. The electroplating apparatus of claim 3, wherein each of the first conductive layer and the second conductive layer is made of titanium.
 6. The electroplating apparatus of claim 1, further comprising a second anode plate arranged in the electrolyte solution opposite to the first anode plate.
 7. The electroplating apparatus of claim 6, wherein each of the first anode plate and the second anode plate is made of titanium.
 8. The electroplating apparatus of claim 1, wherein each of the first drive member and the second drive member includes a conveyor belt, the first drive member and the second drive member are arranged at opposite sides of the clamping assemblies.
 9. The electroplating apparatus of claim 8, wherein the first and second drive members are configured to move the at least one of clamping assemblies in a direction parallel with the first anode plate.
 10. The electroplating apparatus of claim 8, further comprising a first support member supporting the first drive member and a second support member supporting the second drive member, wherein each of the first support member and the second support member comprises: a first end and an opposite second end, the first end and the second end being horizontally oriented and protruding out from the solution; and a recessed portion located between and connected to the first end and the second end, the recessed portion being immersed in the solution, the recessed portion facing toward the first anode plate.
 11. The electroplating apparatus of claim 10, wherein the recessed portion includes a horizontally oriented part, which is generally parallel to the first anode plate.
 12. The electroplating apparatus of claim 1, wherein each of the first support member and the second support member is made of polyvinylchloride.
 13. The electroplating apparatus of claim 1, wherein each of the first cathode plate and the second cathode plate is made of graphite.
 14. The electroplating apparatus of claim 1, further comprising: a first support bar and a second support bar substantially parallel to the respective first and second cathode plates, the first elastic elements being connected between the first cathode plate and the first support bar, the second elastic elements connected between the second cathode plate and the second support bar; and a plurality of holding bars connected between the first and second support bars, and the first anode plate.
 15. The electroplating apparatus of claim 14, wherein each of the elastic elements is a metal spring, each of the support bars and the holding bars is made of polyvinylchloride. 